Surface light emitting device and polarization light source

Abstract

A surface light emitting device includes a polarized light source that emits polarized light; and a light guide plate including a light incident surface on which the polarized light emitted from the polarized light source is made incident, and a light emitting surface that emits light, the light guide plate being made of light transmissive resin having low birefringence in which retardation is one-fourth or less of a wavelength of the polarized light.

1. A surface light emitting device comprising:
 a polarized light source that emits polarized light; and 
 a light guide plate including a light incident surface on which the polarized light emitted from the polarized light source is made incident, and a light emitting surface that emits light, the light guide plate being made of light transmissive resin having low birefringence in which retardation is one-fourth or less of a wavelength of the polarized light. 
 
     
     
       2. The surface light emitting device of  claim 1 , wherein the light transmissive resin is a mixture of a positive birefringent substance and a negative birefringent substance. 
     
     
       3. The surface light emitting device of  claim 2 , wherein the positive birefringent substance is selected from polyvinylidene fluoride (PVDF), polyvinylidene fluoride trifluoroethylene (VDF·TrFE-58) and polyethylene oxide (PEO), and
 the negative birefringent substance is polymethyl methacrylate (PMMA). 
 
     
     
       4. The surface light emitting device of  claim 1 , wherein the light transmissive resin is a copolymer of a positive birefringent substance and a negative birefringent substance. 
     
     
       5. The surface light emitting device of  claim 4 , wherein the positive birefringent substance is selected from polyvinylidene fluoride (PVDF), polyvinylidene fluoride trifluoroethylene (VDF·TrFE-58) and polyethylene oxide (PEO), and
 the negative birefringent substance is polymethyl methacrylate (PMMA). 
 
     
     
       6. The surface light emitting device of  claim 1 , wherein the light transmissive resin is a polymer to which a low-molecular organic substance having a stick-like molecular shape and having anisotropy in polarizability is added. 
     
     
       7. The surface light emitting device of  claim 1 , wherein the light transmissive resin is a polymer to which inorganic birefringent crystal microparticles are added. 
     
     
       8. The surface light emitting device of  claim 1 ,wherein the polarized light source is composed of a group III nitride semiconductor using a non-polar plane or a semi-polar plane as a principal plane, and
 the polarized light source includes a first conductive-type first semiconductor layer, a light emitting layer formed on the first semiconductor layer, and a second conductive-type second semiconductor layer formed on the light emitting layer. 
 
     
     
       9. The surface light emitting device of  claim 1 ,wherein the polarized light source comprises:
 a light emitting element that emits the polarized light; 
 a package base on which the light emitting element is mounted; and 
 a sealing portion that is made of the light transmissive resin and covers the light emitting element. 
 
     
     
       10. The surface light emitting device of  claim 1 , wherein an absolute value of an inherent birefringence index of the light transmissive resin is 3×10 −3  or less. 
     
     
       11. A polarized light source comprising:
 a light emitting element that emits polarized light; 
 a package base on which the light emitting element is mounted; and 
 a sealing portion that is made of light transmissive resin having low birefringence in which retardation is one-fourth or less of a wavelength of the polarized light, and covers the light emitting element. 
 
     
     
       12. The polarized light source of  claim 11 , wherein the light transmissive resin is a mixture of a positive birefringent substance and a negative birefringent substance. 
     
     
       13. The polarized light source of  claim 12 , wherein the positive birefringent substance is selected from polyvinylidene fluoride (PVDF), polyvinylidene fluoride trifluoroethylene (VDF·TrFE-58) and polyethylene oxide (PEO), and
 the negative birefringent substance is polymethyl methacrylate (PMMA). 
 
     
     
       14. The polarized light source of  claim 11 , wherein the light transmissive resin is a copolymer of a positive birefringent substance and a negative birefringent substance. 
     
     
       15. The polarized light source of  claim 14 , wherein the positive birefringent substance is selected from polyvinylidene fluoride (PVDF), polyvinylidene fluoride trifluoroethylene (VDF·TrFE-58) and polyethylene oxide (PEO), and
 the negative birefringent substance is polymethyl methacrylate (PMMA). 
 
     
     
       16. The polarized light source of  claim 11 , wherein the light transmissive resin is a polymer to which a low-molecular organic substance having a stick-like molecular shape and having anisotropy in polarizability is added. 
     
     
       17. The polarized light source of  claim 11 , wherein the light transmissive resin is a polymer to which inorganic birefringent crystal microparticles are added. 
     
     
       18. The polarized light source of  claim 11 ,
 wherein the light emitting element is composed of a group III nitride semiconductor using a non-polar plane or a semi-polar plane as a principal plane, and 
 the light emitting element includes a first conductive-type first semiconductor layer, a light emitting layer formed on the first semiconductor layer, and a second conductive-type second semiconductor layer formed on the light emitting layer. 
 
     
     
       19. The polarized light source of  claim 11 , wherein an absolute value of an inherent birefringence index of the light transmissive resin is 3×10 −3  or less.